Small Missfire, no DTC showing
07-09-2012, 12:01 AM
#1
On The Tree
Thread Starter
Join Date: Aug 2011
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
Small Missfire, no DTC showing So i have a 2000 chevy 5.3l, swapped into my 79 chevy 4x4.
runs about 50-60 psi depending on the vacuum of the engine.
I just recently started having a missfire, not bad enough to throw the check engine light on.
I was thinking it may be because i have a exhaust leak before the o2 sensor for some time now and it may have fouled a plug.
NOT THE CASE. i pulled both sides out and they all looked new still ( only month old AC delco's)
ONE DTC CODE I AM GETTING IS IDLE AIR CIRCUIT HIGHER THAN SET VALUE (or something along those lines)
Im not sure where else to go with this now, i even watched my o2 data..
what i am seeing is a b1s1 o2 is say +3.0% to 7%.. roughly.
while b2s1 o2 is say -.05% to -4% roughly.
i swapped a new o2 in the drivers side and it made no difference.
Does anyone else have any pointers on where to go about next? maybe a stuck injector? clogged? im not sure.
Im leaning towards a injector not getting a full squirt.
runs about 50-60 psi depending on the vacuum of the engine.
I just recently started having a missfire, not bad enough to throw the check engine light on.
I was thinking it may be because i have a exhaust leak before the o2 sensor for some time now and it may have fouled a plug.
NOT THE CASE. i pulled both sides out and they all looked new still ( only month old AC delco's)
ONE DTC CODE I AM GETTING IS IDLE AIR CIRCUIT HIGHER THAN SET VALUE (or something along those lines)
Im not sure where else to go with this now, i even watched my o2 data..
what i am seeing is a b1s1 o2 is say +3.0% to 7%.. roughly.
while b2s1 o2 is say -.05% to -4% roughly.
i swapped a new o2 in the drivers side and it made no difference.
Does anyone else have any pointers on where to go about next? maybe a stuck injector? clogged? im not sure.
Im leaning towards a injector not getting a full squirt.
07-09-2012, 09:57 PM
#3
On The Tree
Thread Starter
Join Date: Aug 2011
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
07-11-2012, 12:38 AM
#6
On The Tree
Thread Starter
Join Date: Aug 2011
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
havent done a injector cut out yet, i eliminated the coil pack factor.. now i just got to figure out which injector is clogged or what happened..
my mistake is when i changed my fuel pump i needed to run a different style filter, and ended up putting it back together and drove it for a while till now i remember i never put that filter on....... probably clogged injector(s)
my mistake is when i changed my fuel pump i needed to run a different style filter, and ended up putting it back together and drove it for a while till now i remember i never put that filter on....... probably clogged injector(s)
07-18-2012, 12:25 AM
#7
On The Tree
Thread Starter
Join Date: Aug 2011
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
well i put another set of injectors in it today. a used set from a wrecking yard ( ya i know..)
but the problem is the exact same. each injector has power going to it ( tested with a noid light) but is it at the right time? idk...
this is strange how just one day it started to do this..
possibly a cam, crank, or knock sensor>
i really need help with this. anything is appreciated..
Thanks
but the problem is the exact same. each injector has power going to it ( tested with a noid light) but is it at the right time? idk...
this is strange how just one day it started to do this..
possibly a cam, crank, or knock sensor>
i really need help with this. anything is appreciated..
Thanks
